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TS EAMCET · Maths · Probability

If \(X\) is a poisson variate with \(P(X=0)=0.8\), then the variance of \(X\) is

  1. A \(\log _e 20\)
  2. B \(\log _{10} 20\)
  3. C \(\log _e 5 / 4\)
  4. D \(0\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(\log _e 5 / 4\)

Step-by-step Solution

Detailed explanation

Poisson distribution \[ \begin{aligned} & P(X)=\frac{e^{-m} m^x}{x !} \\ & \therefore \quad P(X=0)=\frac{e^{-m} 1}{1} \\ & \Rightarrow \quad 0.8=e^{-m} \Rightarrow-m=\log _e 0.8 \\ & \Rightarrow \quad m=\log _e \frac{10}{8}=\log _e \frac{5}{4} \\ & \end{aligned} \] As, we know…